Reuseable, as in great for a combination that might pop the heads off and on rather regularly. (top fuel).

The combustion pressure seal is greater when looking at the stainless steel lock wire, accompanied by a reciever grove in the head. You can lock in a bunch of pressure, where a conventional gasket and fire ring combination would/could be prone to failure. (again think of top alcohol-top fuel cars where cylinder combustion pressures are in excess of what most street cars see in detonation)

Detonation failure resistant, and or allow a builder to use a greater amount of torque to compress head to engine. Oversized bolts and or 18 head bolt combinations..... better more even clamp load than an MLS type gasket where the graphite can compress unevenly with the uneven loads of fastner space arrangement.

And as David has pointed out, hundreds of gasket thickness combinations to allow finite adjustment of combination.

CONS

Sealing water is a pain in the behind, most tend to leak water no matter the system used. On dry block engines like top fuel and or top alchol, no big deal, no water to worry about. Street engine and or saturday night racer...... a cylinder full of water can be a very big deal, and or a puddle under the car, rather disconcerting.
A very fine finish, similar to the recomeded deck and head finish for the COMETICS works well, espeacially when the gaskets have several layers of copper coat on them. Another sealing trick, I've seen spring car engines done with rubber O rings in block and head around the water passages. And lastly, I've used a variant of the rubber O rings, with a thin smear of RTV, allowed to set nearly completly before bolting the thing up. If all else fails, then use a ceramic coolant sealer in the system after assembly. Will seal till next dissassembly.

Fuse...
Some people use head gaskets as investment protection for other parts. Expecting the head gasket to blow when the tune is off and not damage piston, rod, block, etc.. The copper is going to hold that force in, and if its to great for the mechanicals, it will crush em.

As for fire channels through the aluminum, yup. Been there. The copper head gasket survived, although it was somewhat burnt. Had a nice 1/8" fire channel from combustion chamber to exhaust side of head.. Good excuse to mill the heads and increase combustion efficency.

Use copper coat spray, smear a lil RTV on the water passages, and go by the drug store and buy some sodium silicate. If you don't see any leaks you won't need it. One thing we've learned here at work is a drip will seal up when the head gets to operating temp.

Back in the copper gasket/port plate cleavland days. The damn thing would piss a river when cold. Litterlly adding water in the pits...... fire it up, and watch it seal. So long as block temp was above 180, no problems. Get it down around 80 or less... looked like someone cut a hose.

Even mine will seep a little cold. See water drips on the gasket out above the header. But put a little heat in, and its all good.

the guy who posted the avg of thickness, thats all, they(leak) have to be retorked,tend to cut thru after a while on o-ringd heads or blocks,after retorking,leak,move around,more time to clean after sealing to death,did i rem to say they leak,,

we tried them on 2 engines in the last few years,one because a cust had to have them,the other was a drag race boss 429,needless to say we will never do that again,some guys sware by them,they also transfer more heat to the head,quicker,

found this a long time ago I think it came from SCe's web site. Anyway I saved it in my Documents.

Quote:

The Benefits of Using Copper Gaskets:
1. Conductivity. Copper is the standard by which all other conductors are measured, therefore a copper gasket provides superior thermal conductivity, acting to stabilize head and block temperatures which makes tuning easier.

2. 25% coefficient of elasticity. One of the properties of copper is that it stretches before a catastrophic failure, thereby providing an extra measure of safety in case of severe detonation.

3. Strength. Copper (in the form we use) has a tensile strength of approximately 32,000psi, compare this to the 1200 to 1800psi tensile of most facing materials used on conventional performance head gaskets.

2. How to Install Copper Head Gaskets:

• Copper head gaskets are the superior choice for blown, nitrous, turbo-charged and high compression engines.

• If a change in compression ratio is desired, a thicker or thinner gasket can be used. However, reason must be used when adjusting compression ratio with gasket thickness as every .010" change in thickness, nets approximately 2.5cc in volume. This method will never raise an 8.5 to 1 street engine to a 12.5 to 1 race engine.

• The use of o-rings is highly recommended to seal combustion pressure, most notably when there are only 4 head bolts per cylinder. O-ring grooves can be cut into the block or cylinder head. The proper dimensions for .041 stainless wire are: .040 groove width; .030 to .032 groove depth. When cutting/installing stainless o-ring wire, file the ends square to provide a tight joint for the best seal possible.

• When using copper head gaskets thinner than .050, o-ring height should be 25% of gasket thickness.

• Copper head gaskets require the use of a sealant for oil and coolant passages (when applicable). SCE uses and recommends Hylomar. It is available in spray cans or tubes. Always allow Hylomar to tack-up for 5 to 10 minutes before assembly.

• Head gaskets on racing engines should be re-torqued after initial run- in, regardless of type (solid copper or composition). Factory torque specs and sequences are usually adequate. Allow the engine to cool for accurate readings.

• Always use a torque wrench and have it calibrated often.

• Clean, flat surfaces are essential to seal a racing engine. Premium grade head bolts with hardened washers are recommended and studs are preferred.

I am not a hardcore racer myself, but I worked the counter at a performance parts retailer for 2000-2003 and at a warehouse of the same parts from about 6 years before that, and I am by nature pretty serious about what I do. Probably give me a good overview, at least I think it does.

I wouldn't let a copper gasket within 100yards of any vehicle I have, or will ever have.

Copper is obsolete technology. It rarely, rarely works- we did have a monster truck guy, 460 ford, that did use them a few times over a season, but he was the exception in finding any satisfaction with them, and he changed back to Felpro's.
The copper header gaskets are total utter junk, and *forget* about ever reusing a gasket- even the monster truck guy never did that.
And SCE doesn't back their stuff or their distributors at all...

I am not a hardcore racer myself, but I worked the counter at a performance parts retailer for 2000-2003 and at a warehouse of the same parts from about 6 years before that, and I am by nature pretty serious about what I do. Probably give me a good overview, at least I think it does.

I wouldn't let a copper gasket within 100yards of any vehicle I have, or will ever have.

Copper is obsolete technology. It rarely, rarely works- we did have a monster truck guy, 460 ford, that did use them a few times over a season, but he was the exception in finding any satisfaction with them, and he changed back to Felpro's.
The copper header gaskets are total utter junk, and *forget* about ever reusing a gasket- even the monster truck guy never did that.
And SCE doesn't back their stuff or their distributors at all...

If as you say copper head gaskets "rarely, rarely works" why is there plenty of people that use them without problems if they rarely work? True, if you install copper head gaskets incorrectly they could leak, but install Felpro's or Cometics (or any gasket) incorrectly and they too could leak.

The GE silicone containing aluminum that's meant for metals (comes in caulking gun sized tube) works great with copper head gaskets. And the extra heat that a grouted block can generate doesn't seem to faze it either.

If as you say copper head gaskets "rarely, rarely works" why is there plenty of people that use them without problems if they rarely work? True, if you install copper head gaskets incorrectly they could leak, but install Felpro's or Cometics (or any gasket) incorrectly and they too could leak.

The GE silicone containing aluminum that's meant for metals (comes in caulking gun sized tube) works great with copper head gaskets. And the extra heat that a grouted block can generate doesn't seem to faze it either.

Well I have used SCE standard copper gaskets w/ spray on copper coat & currently I am using SCE Titan copper gaskets w/ embossed silicone seals. I have had good luck with both. Block is o-ringed.

I was told by Carroll Carter this past Saturday that he doesn't use copper gaskets anymore. He has gone to Cometics. This came up when I was discussing o-ringing the sleeves on my new block. HMMM, I guess I will be trying a set of Cometics on my Hemi.

I used copper head gaskets with no o-rings on a 10.5:1 chevy 350. Iron vortec heads, stock block (neither had ever been surfaced) and they did seep a bit with the stuff Summit sells to seal them up (Hylomar or something like that). I replaced my cheapy stainless valves and reused the copper gaskets. However, second time around I smeared a thin coat of black RTV on the block, set the gasket on it, smeared a coat of it on the gasket, and bolted it together. It only seeped a TINY amount on one side. It would use about a cup of coolant a year, which was about 10,000 miles. The seep was so minor that it was just a damp spot about 1" by 2" at the seam between head and block.